Automatic chain pin riveting machine



March 8, 1949. WRIGHT 2,463,669

AUTOMATIC CHAIN PIN RIVETING MACHINE Filed Sept. 5, 1947 v 4Sheets-Sheet 1 IO/ Ei- March 8, 1949. WRIGHT 2,463,669

AUTOMATIC CHAIN PIN RIVETING MACHINE Filed Sept. 5, 1947 I 4Sheets-Sheet 2 izz-e I ,[NVENTOE FRED J. WEIGHT) ym/m ATT'Y March 8,1949. wRlGHT 2,463,669

I AUTOMATIC CHAIN PIN RIVETING MACHINE Filed Sept. 5, 1947 4 Shets-Sheets.

Fig-3 f/vve-NTo/e FRED J. WEIGHT,

March 8, 1949. J WRIGHT Q I 2,463,669

AUTOMATIC CHAIN PIN RIVETING MACHINE Filed Sept. 5, 1947 4 Sheets-Sheet4 [/vvE/v7o/e; FRED J. WEIGHT;

HTT X l ular openings Patented Mar. 8, 1949 AUTOMATIC CHAIN PIN RIVETINGMACHINE Fred J. Wright, Columbus, Ohio, assignor to '1 he JeffreyManufacturing Company, a corporation of Ohio Application September 5,1947, Serial No. 772,319

10 Claims.

This invention relates to an automatic chain pin riveting machine, andan object of the invention is to provide an improved machine of thistype in which the pin to be riveted is heated locally while in thechain, after which it is riveted, the operations preferably beingautomatically performed.

Another object of the invention is to provide an automatic chain pinriveting machine which will feed chain while the unheaded ends of pivotpins are successively positioned, heated, and headed or riveted; theheating mechanism preferably being a high frequency electrical heaterwith an inductor head which surrounds the unheaded pin end during theheating operation and which is removed during the heading or rivetingoperation.

Other objects of the invention will appear hereinafter, the novelfeatures and combinations being set forth in the appended claims.

In the accompanying drawings,

Fig. 1 is a front elevational view of a machine incorporating thefeatures of my invention, with parts broken away and in section;

Fig, 2 is a sectional elevational view of the machine takensubstantially at right angles to Fig. 1 and through the approximatecenter of the machine;

Fig. 3 is a piping diagram of the air and hydraulic circuits employed toperform certain functions of the automatic machine; and

Fig. 4 is a wiring diagram of the machine.

Referring particularly to Figs. 1 and 2 of the drawings, the machineincludes a main frame l formed of a pair of parallel spaced-apartupstanding plates 1 I, I l interconnected by a plurality of cross platesand having generally rectangl2 adjacent the top thereof. Mounted in thetop of the main frame 10 is a pair of hydraulic rams l3 and M which arein the form of double acting hydraulic cylinder rams, the cylinders ofwhich are rigidly attached to laterally spaced plates l5 and I6,respectively, which are welded or otherwise rigidly attached to the mainframe members H and are upstanding and parallel and located on oppositesides of the openings l2. As clearly illustrated in Fig. 1 of thedrawings, the rams l3 and M are oppositely positioned so that they faceeach other and are in alignment on a horizontal axis which extendssubstantially across the middle of the window provided by the openingsl2.

Reciprocating plungers, headers or riveters l1- and I8 of the hydraulicrams l3 and I4, respectively, are in alignment on a horizontal axis andare adapted to be moved toward and from each other to rivet the heatedunheaded end of a chain pin, such as the pins I9 of chain 2! theunheaded end of one of which is seen at the left in Fig. l of thedrawings. The chain 29, whose pins 19 are to be riveted, is supportedupon a horizontal platform 2| rigidly attached to the main frame In andin fact forming a part thereof and extending substantially through thecenter of the window l2-l2.

Platform 2| has an elongated slot 22 extending rectilinearly down itscenter (see Fig. 2) below which there is a reciprocating carriage 23mounted for rectilinear sliding or reciprocating motion in spaced guides24. The carriage 23 carries one or more pivoted pawls 25 which havetheir upper ends projecting through the slot 22 and which are mountedfor pivotal movement on horizontal axes. The upper ends of the pawls 25extend between the blocks of the chain 20 and operate in an obviousmanner to move the chain 20 forward as the carriage 23 moves forward,since the pawls 25 are held against limited clockwise rotation by stoppins 26. During reverse travel of the carriage 23 the pawls 25 canratchet over the barrels of the chain 20, thus to engage a succeedingblock and move the chain 2!! forward one pitch length for eachreciprocation of the carriage 23, thus successively bringing pins itinto alignment with the plungers or riveters I! and 18.

It is evident that the horizontal platform 2| is so positioned that thepins I 9 in moving thereover will travel along a horizontal plane whichis in alignment with the axis of the plungers or riveters l1 and I 8. Itis also evident that the vertical position of the pins 19 is alsobrought into alignment with said plungers H and i8 by the reciprocatingcarriage 23 and cooperating pawls 25.

Reciprocation of the carriage 23 to advance the chain 20 and positionthe pins ll for riveting is effected by a double acting air feedcylinder 27, the cylinder of which is mounted on a platform 28 formingpart of the main frame l0, and the piston rod of which is attached by ayoke 29 to the carriage 23.

The pivot pins !9, as they exist in the chain 2!] prior to the rivetingoperation, preferably have a head on one end, the other end beingunheaded. In Fig. 1 of the drawings the pin I9 is shown with a head onthe right-hand end, the left-hand end being unheaded. It is preferredthat in building up the chain with the unriveted pins, as it travelsover platform 2!, the pins l9 as will be successively reverselypositioned with respect to the chain 20. That is, each succeeding pinwill have its head on the opposite side of the chain and likewise willhave its unriveted end on the opposite side of the chain.

The chain 20, as it is fed to the riveting machine, is entirely unheatedand a feature of the invention is the provision of mechanism, preferablyautomatic in character, which will locally heat the projecting unheadedend of each pin 19 to a high temperature, preferably by high frequencyelectrical induction heating, after which the induction heatingapparatus is removed from the unheaded pin end and the rams l3 and [4simultaneously actuated to move toward each other and through the actionof the plunger, header or riveter IT or E8, as the case may be, form ahead on the heated pin end, thereby to rivet each pin l9 of chain 20.

Mechanism for heating successive unheaded pin ends which projectalternately from opposite sides of the chain 23 and for riveting saidheated pinends will now be described. Between the plates ll of the mainframe it? is a table 30 which is mounted for up and down reciprocalmotion on a double acting raise or elevating air cylinder 3! which ismounted in a sub-frame 32 carried by front plate ll of main frame it.Guide means to insure that the table 33 is always horizontal is providedwhich includes a transverse shaft 33 journaled in brackets dependingfrom the table 30 and carrying rigidly attached gears on opposite ends,one of which is seen at 3 The gears 34 mesh with racks, one of which isseen at 35, which are attached .to an upstanding plate of the sub-frame32.

On the front the platform carries a pair of plain rollers, one of whichis seen at 36, there being one adjacent each end thereof, the rollers 36cooperating with plain track bars, one of which is seen at 31, which arecarried on the front plate of the sub-frame 32. The shaft 33, gears 34and racks 35 insure movement of the table 33 in parallelism, and therollers 36 and tracks 31 guide it and prevent rotation thereof, at thesame time insuring intermeshing of gears 33 and racks 35.

At opposite sides of the table 33 there is duplicate mechanism, that onthe right-hand side being illustrated particularly in Fig. l of thedrawings, which shall now be described, it being understood that similarmechanism is present on the left-hand side. Slidably mounted in guidemeans 38 (see Fig. 2) carried by the table 33 is a base frame 39 whichis adjustable on a horizontalv axisparallel with the axis of the pins I9and'with the axis of the plungers ill and 88. A common adjusting rod 43has threaded relation with the two base frames, one of which is seen at39, and by rotating said rod 40 said base frames may be simultaneouslyadjusted toward or from each other.

Slidably mounted on the base frame 39 is a high frequency transformersupport ll which is slidably adjustable by a double acting air cylinder42, the cylinder of which is also mounted on the base frame 39 and thepiston of which is attached to the transformer support M. The support llcarries. a high frequency transformer 43, there being a similar highfrequency transformer fi l mounted on the opposite side of the machinewhich is controlled by a double acting air cylinder :35 (see Fig. 3)which is similar to cylinder 32 and is mounted on a separate base framesimilar to base frame 39, as above mentioned.

The high frequency transformers 33 and 44 are provided with similarsingle loop fluid cooled induction heads or inductors 46 and 41,respectively, which selectively are adjusted to encircle the unheadedend of a pin it] and to heat it for a predetermined period so as tobring it up to a temperature at which it can be readily riveted, afterwhich the head 13 or M, as the case may be, is moved axially of the pinl9 and then lowered to be out of the way of the plungers, headers ofriveters ll and it which are simultaneously moved toward each otheragainst the pin l9 to form a head on the previously heated portion.

Many of the features of the high frequency transformers 43 and 44 andthe induction heads 36 and H, as well as some of the features of thecontrol circuit therefor, are involved in induction heating apparatusknown commercially as Tocco Junior manufactured and sold by the OhioCrankshaft Company of Cleveland, Ohio. However, there have been a numberof important modifications of the standard circuitof the 'I'occo Juniorand the particular assembly of mechanical parts above described isentirely different from the Tocco Junior unit.

Before proceeding with a description of the air, hydraulic andelectrical circuits, it may be well to describe briefly the successivesteps in-' volved in a typical case of riveting pins of a chain. Aspreviously mentioned, the chain 20 is preferably assembled with theunheaded ends of the pins i9 projecting successively on opposite sidesof the chain 23. The chain is then laid on the platform 2i and the partswill be essentially in the positions illustrated in Figs. 1 and 2, ex-

cept that the double acting cylinder 31 will be in its lower positioninstead of its upper, position, as illustrated, and consequentlythe-table30 will 1 be lowered, with the transformers .43 and 44 and theinductors 4t and ll lowered entirely below the.

plungers if and it. In addition, the chain 20 will be considered in aposition where it is necessary to move it forward the length of one linkto bring a pin IS in position to be riveted.

The first operation is energization of the double acting feed cylinder21 which will move the chain 23 forward to position a pin I9 inalignment with the plungers, headers or riveters H or l8. Thereafter thedouble acting feed cylinder 21 reverses its operation and is prepared tomove the chain forward to align the succeeding pin. The raise orelevating cylinder 3| is then energized to raise or elevate the table 30and the transformers 43 and A l and the inductors 46 and 41 into thepositions illustrated in Fig. 1 of the drawings. Thereafter doubleacting air cylinder 42 or its counterpart E5 is energized to slidetheinductor 53 or ll over the unheaded end of the pin l9, only one of thesecylinders 42 or its counterpart being thus energized, depending uponwhether the unheaded end of the pin- [3 extends to theright or left.

As illustrated in Fig. 1 of the drawings it will be the lefthandcylinder 415 which is similar to cylinder 42 which will be thusenergized, and the loop type head or inductor M will move over thealigned unheaded end of pin i3 which projects beyond the adjacent sidebar of the chain 20. When the inductor or head ll is thus positioned, itwill be energized for a predetermined length of time adequate to heatlocally the unheaded end of pin l9 by induced high frequency electricalcurrent. After a predetermined time, which may be adjusted bycontrollinga timer, the head All and transformer 33 will be moved to theleft (as seen in Fig. 1) under the action of the double, '7

acting cylinder 45 to remove the head or loop 47 from the heatedunheaded pin end. Thereafter, elevating or raise cylinder 3| will beactuated to lower the table and thus lower the transformers 43 and 44and their inductors 46 and 41 so that the latter are entirely below theplungers I! and I8. Hydraulic rams I3 and I4 are then simultaneouslyenergized by hydraulic fluid under high pressure so that the plungers I!and I8 move toward each other, plunger I1 contacting the previouslyformed head on pin I9, and plunger I8 forming a head on the heated endof said pin l9. The contacting faces of the plungers I1 and I8 arepreferably cupped or recessed so as to form a head on the heated end ofpin I 9 in the one instance and to conform to the previously formed headon the pin I9 in the other instance.

After the plungers I1 and I8 have moved toward each other and compressedthe pin I9 between them so as to build up a predetermined hydraulicfluid pressure in the conduits or feed lines leading to one of thehydraulic rams I3, I4, the plungers I1 and I8 are retracted to thepositions illustrated in Fig. 1 of the drawings and the machine is readyto complete another cycle of operation, as above described.

Attention is now directed to Fig. 3 of thedrawings which illustrates thehydraulic rams I3 and I4 and the hydraulic circuit which controls themand also illustrates the various air cylinders and their controlcircuits. An air line, pipe or conduit 48 is provided and delivers airunder pressure to the several cylinders 27, 3|, 42 and 45 under thecontrol of individual valves. For example, solenoid actuated valve SI isprovided for feed cylinder 27, the valve being of standard constructionand spring biased so that when its solenoid is deenergized it willdeliver air to move the piston of cylinder 21 to the right or, in otherwords, retract it. Conversely, when its solenoid is energized thecylinder 21 will be expanded or the piston moved to the left. There isan automatic returning limit switch LSI associated with cylinder 21 andwhich is actuated when the piston thereof reaches the end of its stroke,automatically resuming its normal position when the piston is returned.

Associated with and controlling double acting cylinder 45 is a solenoidactuated valve S3 which is similar to the valve SI above described.There is a similar valve S4 associated with and controlling doubleacting cylinder 42. Associated with cylinders 45 and 42 are normallyclosed limit switches LS2 and LS3, respectively, which are open whentheir respective cylinders 45 and 42 are in their retracted or outpositions, that is, when they have moved the inductors 4G or 41, as thecase may be, outwardly to the positions illustrated in Fig. 1 of thedrawings.

The double acting air cylinder 3| is controlled by a solenoid actuatedvalve S2 which is similar to valves SI, S3 and S4. Associated with thepiston rod of double acting cylinder 3| are limit switches LS4 and LS5.Switch LS4 is a double contact switch, one of the contacts of which isnormally closed, the other normally open, said switch being actuatedwhen the piston rod of cylinder 3! is retracted. Switch LS5 is normallybiased to its open position and is closedwhen the piston of cylinder 3|reaches the upper limit of its stroke.

It is, of course, evident that all of the solenoid operated valves SI,S2, S3 and S4. control the delivery of air from air line 48 to theirrespective 6 double acting cylinders and at selected ends thereof while,of course, venting the opposite side of the cylinder to atmospherewhenever a cylinder is actuated.

The hydraulic circuit for controlling the hydraulic rams I3 and I4includes a pump 49 which derives hydraulic fluid, such as oil, from atank 50 and delivers it over a pressure line or conduit 5| to a controlvalve 52 which is biased to a central no-load by-pass position and whichmay be reversely operated by either of the solenoids S5 or S? whichreversely control the core thereof.

If solenoid S5 is energized, valve 52 will be actuated so as to deliverhydraulic fluid under pressure to conduit 58, which has two branches I58and 258, energizing hydraulic rams I3 and I4 to cause the plungers I!and I8 to move inwardly or toward each other. Once this movement isstarted it will normally continue until a predetermined pressure isbuilt up in the hydraulic conduit 58 and branches I58 and 258 adequateto actuate combination pressure relief valve and control switch PSIwhich provides a pressure relief by-pass to the tank 58 over an obviouspipe or conduit. That is, predetermined pressure in conduit 58 andbranches I58 and 258 will cause relief valve PSI to open and willsimultaneously close an electric switch for a purpose hereinafterdescribed.

If solenoid S1 is energized the hydraulic fluid under pressure will bedelivered to the pipe or conduit 59 to energize rams I3 and I4 to movethe plungers I7 and i8 outwardly or away from each other and theirmovement will automatically continue for the full stroke, whereuponcombination pressure relief valve and electric switch PS2 will beactuated to by-pass the hydraulic fluid to tank 58 and to actuate theelectrical switch of PS2.

To provide for the simultaneous movement of the plungers I? and i8 atsubstantially the same rate toward each other, there is a rotaryhydraulic motor in each of the branch conduits I58 and 258 designated65} and 6!, respectively, which are coupled together by a flexiblecoupling 62. This arrangement insures substantially equal flow ofhydraulic fluid in the two branch conduits I58 and 258, thus insuringsubstantially the same rate of movement for the plungers I1 and i8.

To take care of any inequality or leakage, there is a pressure reliefvalve connected across the input and output lines of branch conduits I58and 258, the relief valve for the former being designated 63 and thatfor the latter being designated 64. These valves are set at a relativelylow pressure, such as one hundred and fifty pounds per square inch, sovthat if either plunger H or iii reaches the end of its stroke before theother, valve 83 or 64 associated with the ram l3 or I4, which has notfinished its stroke, will open and allow hydraulic fluid to by-pass themetering motor E8 or 6!, as the case may be, causing said slow plungerI! or I3 to finish its complete stroke. If hydraulic fluid underpressure is delivered to the conduit 59 to retract the plungers I! andit, the branch conduits 58 and 258 and the conduit 58 provide a returnpath for the hydraulic fluid which is delivered to the tank 50 throughcontrol valve 52. The return movement of the plungers ll and I8 is notmetered through the motors 60 and 6| but is by-passed through returncheck valves in the relief valves-(i3 and 64. If the hydraulic fluidunder pressure is delivered to the conduit 58, conduit 59 will be thereturn conduit and valve '52 will deliver it to tank 50.

frequency Fig. 4 of the drawings illustrates the wiring diagram of theelectrical circuit in which the limit switches and solenoid operatedvalves of Fig. 3 are included diagrammatically. The electrical circuitincludes three principal parts which are interconnected in a mannerobvious from the following description. Said circuit includes analternating current motor 65 which is energized from three power line66. Motor 65 drives a high alternator or generator 61 which in the T0000Junior unit previously mentioned and in the system of the instantinvention may develop alternating electrical current having a frequencyof approximately ten thousand cycles per second, which is delivered tohigh frequency transformers 43 and 44, selectively, and to inductors 46and 41, selectively, which are permanently connected to the secondariesof said transformers 43 and 44. Capacitators or condensers '68 areconnected across the primary terminals of transformers 43 and 44,respectively, to improve the power factor. The control circuits by whichtransformers 43 and 44 are selectively energized for predetermined timesduring the cycle of operation of the riveting machine will be describedhereinafter.

Branching from two of the power lines 66 is a single phase line illwhich delivers power to mains H and 12 which are the mains for theprincipal control system. Line l also energizes a transformer 13, theoutput of which energizes mains 14 and 15 of an auxiliary controlcircuit.

It may be stated that a number of the standard electrical parts of theTocco Junior unit are not illustrated in the wiring diagram as they formno part of the present invention. It may also be mentioned that thereason for the two separate mains H, 32 and l4, 15 is that in thecommercial unit the former is of 220 volt circuit and the latter 110volt circuit; the transformer 13 therefore being a two to one step-downtransformer.

The individual circuits of the electrical control system can best bedescribed in connection with a description of one complete cycle ofoperation which shall now be given. Upon closing a master control ordisconnect switch for the three phase power line 66, it is evident thatmotor 65 will be energized, thereby developing high frequency electricalvoltage by generator Bl. Mains ll, 12 and l4, l5 will likewise thus beenergized. The automatic pin riveting machine is then in condition to beset into operation and once set into operation it will continue tooperate automatically to rivet the successive pins I9 until it isstopped, there being certain flexibility as shall be pointed out in thedescription to follow.

Automatic operation is initiated by closing manual switch MSI whichenergizes the light Ll indicating that the system is in automaticoperation. The initial starting of the automatic operation requires theoperator to close push button PBI which energizes the solenoid or coilof relay CI over an obvious circuit. Coil or solenoid of relay Cl isheld energized over an obvious circuit including the upper normally opencontacts of relay Cl and the upper normally closed con.- tacts of limitswitch LSl. The lower normally open contact of relay Cl on closingenergizes solenoid valve SI which causes the feed cylinder 21 to moveforward and advance chain with the pin 19 in position to be riveted. Atthe forward end of its stroke the feed cylinder 21 actuates limit switchLSl which breaks the hold circuit for the relay Cl, causing it todeenergize, which deenergizes the solenoid of valve SI, thereby causingthe feed cylinder 2'! to retract to its 8 initial feeding position whereit will be ready to feed the chain 20 forward another link length whensubsequently energized at the start of an other cycle.

Simultaneously with the release of relay Cl by operation of limit switchLSI it closes a circuit through its lower and normally open contacts toenergize the coil or solenoid of a relay C2 which is provided with ahold circuit through its upper normally open contacts and through theupper normally closed contacts of relay C5 over an obvious circuit.Relay C2 in energizing closes the circuit of solenoid valve S2 over itslower normally open contacts.

As previously described, solenoid $2 on being energized causes raise orelevating cylinder 3| to expand, raising the table 30 and thetransformers 43 and 44 and inductors 46 and 41 to the positionillustrated in Fig. 1 of the drawings, with the axes of the loopinductors or heads 46 and 41 in alignment with the axis of the pin l9 tobe riveted and the axis of the plungers or headers l1 and I8.

When the table 30 and parts which it carries are also elevated orraised, limit switch LS5 (found to the left of the wiring diagram) isactuated and this energizes a magnetic clutch 19 of a standard motordriven timer TRI, the effect of which is to connect a cam to the shaftof the continuously running motor of said relay so that the cam willstart to rotate. It may be stated that the motor of the relay TRI isdirectly across the mains 14 and 15 and runs continuously once the mainswitch of the system is thrown. Furthermore when the switch LS5 isenergized it not only actuates the clutch 19 to start the timing caminto operation, but it effects an initial closing of the normally opencontacts of relay TR! and these contacts remain closed until the motor80 has rotated the cam of the relay for a predetermined time which maybe adjusted by an operator.

Thus immediately upon the energization of clutch 19 in response toclosing of limit switch LS5 the two normally open contacts of the relayTRI are closed, the upper providing a holding circuit for the clutchuntil the cam has rotated a predetermined amount, and the lower closingan obvious circuit for the coil or solenoid of relay C9, closing itsthree normally open contacts. The center contact of relay C9 closes anobvious circuit through the coil or solenoid of relay C5 which closesits bottom normally open contact and opens its top normally closedcontact, the latter breaking the holding circuit of the coil of relayC2. The coil or solenoid of relay C2 is, however, held in energizedcondition over an obvious holding circuit directly through the lower,now closed contact of relay C5, thus maintaining the table 30 and allthe elements carried by it in the elevated position illustrated inFig. 1. It may be stated that the timer TB! is a standard unit on theT0000 Junior previously mentioned.

The upper and lower contacts of the relay C9 operate to close a circuiteither to the solenoid of relay C3 or to the solenoid of relay C4 overobvious paths, depending upon the position of the contact of alternatelyshiftable relay designated S6, of which a cam operated Struthers- Dunnrelay of standard design is an illustration. This relay S6 includes ashiftable switch element 16 which is connected to main H and which isoperated by cam 11 so that every time the solenoid of relay S6 isenergized the switch element 16 moves alternately to one contact oranother.

9 In the positionof the switch element 16 illustrated in Fig. 4 of thedrawings the relay C3 is energized through the upper contacts of therelay C9. Also the signal light L2 is energized to indicate the positionof the switch element 16 and, what is of particular significance, toindicate which of the inductors 46 or 41 is to be energized.

Relay C3 on energizing closes its two normally open contact-s, the upperone of which energizes the solenoid of heavy duty contactor or relay S8in a high frequency circuit which energizes the transformer 43 and theinductor 41 from the high frequency generator 61, over an obviouscircuit which includes the normally closed contacts of a relay ICRIwhich is in the left-hand control circuit and which is now closed due tothe fact that its coil is connected in parallel with the coil C9 andconsequently is energized simultaneously therewith by the lower contactof the timer relay TRI. There is also a signal light 18 connected acrossthe terminals of the coils of relay C9 and ICRI, thus indicating theyare energized.

The lower contact of relay C2 energizes the solenoid of control valve S3which energizes air cylinder 45 to move the high frequency transformer44 and inductor or head 41 to the right, as viewed in Fig. 1 of thedrawings, thereby causing the inductor 41 to encircle the unheadedportion of the pin I9 which is to be heated by electrical high frequencyinduced heat.

At the end of the heating time determined by the timer 'I'Rl its twocontacts are open, thus deenergizing relays C9 and ICRI and deenergizingthe transformer 44 and inductor 41. The deenergization of relay C9breaks the previously described circuit for the solenoid of relay C5.However, said solenoid of relay C has two very obvious. circuits whichinclude limit switches LS2 and LS3. Limit switches LS2 and LS3 arebiased to closed position, but they are open when the two transformers43 and 44 and inductors 46 and 47 are in the retracted positions, asillustrated in Fig. 1 of the drawings and as previously described.However, since transformer 44 and inductor 41 have moved to their inwardpositions under the conditions previously described, limit switch LS2will be closed and thus provide a holding circuit for the solenoid ofrelay C5. This relay will remain energized until air cylinder 45 isenergized to move the transformer 44 and the inductor 41 to the left oroutward, which will open limit switch LS2, thus breaking the holdingcircuit for the coil of relay C5 since limit switch LS3 is already openbecause cylinder 42 is in its contracted or outer position.

The deenergization of relay C5 breaks the previously described holdingcircuit for the coil of relay C2 involving the lower contact of rela C5,thus deenergizing relay C2 which opens the circuit to solenoid S2 whichreturns to its normal position and actuates elevating cylinder 3| tolower it.

At the beginning of the cycle, when raise cylinder 3i first started toraise the table 30 it released limit switch LS4 so that it moved to itsnormal position as illustrated in Fig. 4 of the drawings which energizedthe coil of relay C5 over an obvious circuit including normally closedupper contacts of pressure switch PSI. After the inductor 41 had heatedthe unheaded end of pin 19 for a time determined by the relay TR!, andthe table 30 was lowered as above described, limit switch LS4 wasactuated by the contraction of cylinder 3|, breaking its lower contacts,However, relay C6 is provided with a holding circuit which by-passes thelower contacts of limit switch LS4 through the lower contacts of saidrelay C6, thus holding relay C6 energized for the time be- When limitswitch LS4 is actuated on the return of the table 30 to its lowerposition, its upper contacts are closed and they energize the solenoidor coil of relay Cl through the upper contacts of relay C6 which is nowenergized. Relay C! on energizing closes the circuit through its lowercontacts and a control switch MS2 to energize the operating solenoid ofthe Struthers-Dunn relay SS, thus switching the switch element 16 fromthe position shown to its alternate position where the light L3 isenergized and relay C4 is energized instead of the relay G5, on thesubsequent operation of the timer TRI and relays C9 and ICRI during thenext heating cycle, the purpose, of course, being to energize thetransformer 43 and inductor 46 on the next heating cycle as the pins I 9are successively extended through the chain 28 in opposite directions.

With the inductors 45 and 4! lowered out of the paths of the plungers l1and I8 and with the unheaded end of the pin 19 heated to a very hightemperature which, for example, may be of the order of l600 to 2200Fahrenheit, the relay C! on energizing, in addition to operating therelay S6, also energizes solenoid valve S5 over its upper contacts whichcontrols the hydraulic valve 52, as above described, to supply hydraulicfluid under pressure to the line 58 and the branch lines I58 and 258 tomove the plungers, headers or riveters I! and I8 inwardly against thepin l9 and to form a head on the heated unheaded end of said pin l9,since the headers l1 and I8 are formed as dies for this purpose.

The headers l1 and I8 are preferably designed or shimmed with apredetermined length so that in completing their riveting operation thepistons of the rams I 3 and I4 travel the full stroke thereof. Afterboth said rams l3 and I4 have traveled their full stroke, pressure inthe lines 58, I58 and 258 will build up and actuate the combination highpressure relief and pressure responsive switch PSI which opens itsnormally closed contacts and deenergizes the coil of relay C6, thusdeenergizing relay Cl and solenoid valve S4.

Pressure responsive switch PSI through its normally open contacts whichare closed in response to pressure above mentioned, energizes the coilof a relay C8 through the normally closed lower contact of pressureresponsive switch PS2 associated with the conduit 59. Relay C8 has aholding circuit through its normally open upper contacts and thenormally closed lower contacts of pressure switch PS2, thus holding itindependent- 1y of pressure switch PSI. The lower contacts of relay C8energize solenoid valve S! which operates valve 52 to deliver hydraulicfluid to the conduit 59 and connects conduit 58 to tank, thereby movingthe plungers I1 and I8 outward. After they have both moved outward tothe ends of their stroke, hydraulic fluid pressure will build up inconduit 59 to actuate the pressure responsive switch PS2 which at itslower contacts breaks the holding circuit for relay C8, deenergizing it,which in turn deenergizes the operating solenoid S1 for hydraulic valve52, allowing it to return to neutral and providing a no-load by-pass forthe pump 49.

The relay C7 previously mentioned, which controls the Struthers-Dunnrelay S6 so that inductors 46 and 4! are normally alternately energized,

effects this control through its lower contacts and manual switch MS2previously mentioned. In case the pins l9 are all extended through thechain 20 in the same direction, that is, with all heads on one side ofthe chain, manual switch M82 is left in its open position, as aconsequence of which the energization of coil Cl will not actuate therelay $8. In this case the inductor 46 or 41, as the case may be, willbe successively returned and positioned over the pins to heat themrather than the normal alternate operation. Also in case a pin i9 ispresented at the operating position in which the unheaded end extends inthe wrong position, as determined by the lighting of light L2 or L3which indicates which of the inductors 46 or 41 is .to be energized, itis only necessary for the operator to push the button PB3 which willmanually energize th Struthers- Dunn relay S3 and reverse the positionof the switch element 16, thereby selecting the other of the inductors4B or 41 to be energized.

After the machine has completed one cycle of operation it will normallyproceed with succeeding cycles. To effect this the manual switch MSl,above mentioned, is left closed. When the switch PS2 is actuatedfollowing the outward movement of the plungers I1 and 18 it closes itsupper contacts which are in series with manual switch M55 and pushbutton P32, and energizes the coil of relay Cl, starting a new cycle ofoperation following that previously described.

If it is desired to terminate the operation of the machine following onecomplete cycle, manual switch MS! is left open. Furthermore, if theoperator desires merely to terminate the automatic operation of themachine following the completion of any cycle, it is only necessary forhim to push the button PBZ and hold it depressed until the cycleautomatically completes. Thereafter, he can release push button PB2 butthe machine will not automatically start in operation again until pushbutton PB! is pushed to actuate relay CI, as previously described.

In the previous description it was assumed that the Struthers-Dunn relayS6 was in such a position that it closed the circuit through switch element 16 to relay C3.

In the normal operation the succeeding cycle will take place the same asthe first cycle, except that switch element 16 would move to energizelight L3 and upon the operation of relays C9 and ICE! the coil of relayC4 would be energized instead of the coil of relay C3; During this cyclerelay C4 through its upper contacts energizes solenoid valve S4 to movethe cylinder 42 inward, thus moving the inductor 48 over the unheadedend of a pin I9. The lower contact of relay C4 will energize thesolenoid of heavy duty contactors S9 and thus energize the inductor Mfrom the high frequency generator 6! through the contacts of relay ICRIwhich are also closed.

The second cycle of operation is therefore essentially the same as thefirst, except for the inward movement of the inductor 46 instead of theinductor 41, together with the associated transformer 43 instead of thetransformer 44, and with the energization of said transformer 43 andinductor 46 instead of the transformer 44 and inductor 41.

As previously described, the relay TR! has a variable predeterminedcycle of operation which determines the heating time for the pins. Thisheating may be determined at any time by manually releasing the clutch19 through a normally closed push button switch 81 which is in seriestherewith, the efiect of actuating push button 8| (iii 12 being the sameas though relay TRI completed its normal cycle of operation.

From the above description it is evident that the invention in its mostspecific aspect is directed to apparatus for the riveting of chain pins.In certain broader aspects, however, it is evident that this is only oneillustration of a forging operation of a metal, the metal must beessentially one containing iron so that the induced high frequencycurrents will develop induced heat in a well known manner. In a stillbroader aspect of the invention, forging need not take place, but themere heating of the iron of a metal element may be involved as a part ofa heat treating process.

Obviously those skilled in the art may make various changes in thedetails and arrangement of parts without departing from the spirit andscope of the invention as defined by the claims hereto appended, and Itherefore wish not to be restricted to the precise construction hereindisclosed.

Having thus described and shown an embodiment of my invention, what Idesire to secure by Letters Patent of the United States is.

1. An automatic pin riveting machine including a support for a chainhaving unheaded pins to be riveted, a pair of spaced aligned rams havingpin riveting heads positioned to move toward and away from each otherand to rivet a heated pin when moved toward each other, a pair ofelectrical heaters, means operable to position a selected heateradjacent an unheaded pin and to heat it, means for removing said heaterfrom the heated pin, and means to feed said rams to clamp the heated pinbetween them and rivet the pin to the chain.

2. An automatic pin riveting machine including a support for a chainhaving unheaded pins to be riveted, a pair of spaced aligned rams havingpin riveting heads positioned to move toward and away from each otherand to rivet a heated pin when moved toward each other, a pair ofinductor coils, means operable automatically to position a selectedinductor coil over an unheaded pin and to heat it by induction, meansfor automatically removing said inductor coil from the heated pin, andautomatic means to feed said rams to clamp the heated pin between themand rivet the pin to the chain.

3. A pin riveting machine including a chain support, a ram, means forpositioning a chain on said support with an unriveted pin aligned withsaid ram, a loop electrical heater, means for moving said loop heater toa position over and encircling the end of said unriveted pin to heat it,means for removing said heater from said pin after it is heated, andmeans for energizing said ram to rivet said pin, all said meansoperating automatically under the control of control mechanism.

4. A pin riveting machine including a chain support, a ram, means forpositioning a chain on said support with an unriveted pin aligned withsaid ram, a loop electrical heater, means for moving said loop heater toa position over and encircling the end of said unriveted pin to heat it,means for removing said heater from said pin after it is heated, andmeans for energizing said ram to rivet said pin after said loop heateris removed.

5. A chain pin riveting machine including a pair of opposed, alignedspaced apart hydraulic rams, a support for a chain constructed toposition a chain pin in a plane passing through said rams, means forfeeding said chain to align said pin with said rams, a pair of highfrequency electrical transformers each having an inductor head adaptedto be positioned over an unheaded end of a chain pin, the twotransformers and inductors being positioned to head oppositelyprojecting pin ends, a vertically adjustable platform, horizontallyslidable frames on said platform, each carrying one of said transformersand its inductor, means for elevating and lowering said platform firstto position the inductor in alignment with a pin and thereafter toremove it from said position, means for reciprocating a selected one ofsaid frames first to position an inductor over a pin and thereafter toremove it therefrom after it is heated, and means for energizing aselected transformer and inductor to heat the associated pin end.

6. A chain pin riveting machine including a pair of opposed, alignedspaced apart rams, a support for a chain constructed to position a chainpin in a plane passing through said rams, means for feeding said chainto align said pin with said rams, a pair of high frequency electricaltransformers each having an inductor head adapted to be positioned overan unheaded end of a chain pin, the two transformers and inductors beingpositioned to head oppositely projecting pin ends, a verticallyadjustable platform, horizontally slidable frames on said platform, eachcarrying one of said transformers and its inductor, means for elevatingand lowering said platform first to position the inductor in alignmentwith a pin and thereafter to remove it from said position, means forreciprocating a selected one of said frames first to position aninductor over a pin and thereafter to remove it therefrom after it isheated, and means for energizing a selected transformer and inductor toheat the associated pin end.

7. A chain pin riveting machine including an electrical heater adaptedto be moved to a position over and encircling an unheaded pin end andheat it, means operable automatically to position said heater over astationary unheaded pin end and heat it and thereafter to remove ittherefrom, and ram means operable to form a head on the heated end ofsaid pin.

8. A chain pin riveting machine including an electrical loop inductoradapted to be positioned over and encircling an unheaded pin end andheat it, means operable to position said inductor over an unheaded pinend and heat it and thereafter to remove it therefrom, and hydraulic rammeans operable to form a head on the heated end of said pin.

9. Mechanism for heating a rod or shaft end containing iron, includingmeans for supporting said rod or shaft end in a predetermined position,a loop inductor, means for moving said loop inductor to a position overand encircling said rod or shaft end, means for energizing said loopinductor with high frequency electrical current to heat said rod orshaft end by induction, and means for removing said loop inductor fromthe heated rod or shaft while said rod remains in said predeterminedposition.

10. Mechanism for forging a metal element containing iron which includesmeans for positioning and supporting said element in a predeterminedposition, a loop inductor, means for automatically extending said loopinductor over said metal element, means for energizing said loopinductor with high frequency electrical current to heat said metalelement by induction, means for automatically removing said loopinductor from the heated element While the latter remains in saidpredetermined position, and means for automatically forging the heatedelement to alter its shape.

FRED J. WRIGHT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,308,399 Cutter July 1, 19191,878,458 Blanchet Sept. 20, 1932 1,901,334 Reed Mar. 14, 1933 2,275,763Howard et 'al Mar. 10, 1942

